Chemplant Fire in Louisiana

Earlier this week there was a significant fire at a chemical facility in Duson, LA (according to the company web site the location is actually in Rayne, LA, but the news reports are consistent in calling it Duson). The facility appears to be a distribution center for the company’s oil field chemicals, though some blending may take place in at least one of the buildings on site.

The News Reports

News reports (here, here, here, and here) would seem to indicate that the fire started with an initial explosion, followed by a number (one witness reported “dozens of explosions in a half hour to one-hour period”). These reports, combined with a news photo of the incident (which shows the 10 storage tanks on site intact during the active phase of the fire) would indicate that the fire took place in the open storage of chemical containers (55-gal drums, plastic and steel totebins).

A company statement quoted here notes that “there are no uncontained spills”.

Google satellite view shows that a large portion of the facility is given over to open storage of chemical containers. Google street view of that storage area shows that it consists of a concrete pad surrounded by a 6” to 8” curb to contain spills. Street view from the back side of the plant shows that the ‘tank farm’ containing 10 storage tanks (4k-gallons each?) is on the same pad but is surrounded by an additional 8” to 10” curb.

The chemicals reported on site reported include a wide variety of oil field chemicals. Many of these chemicals would have flammability and corrosivity hazards associated with them. A close look at the Street View of the storage tanks shows that at least two of them contained flammable materials. The flammability of the typical oil field chemicals is due to the solvents used, which typically would include xylenes, methanol, toluene and benzenes.

Analysis

The investigation of this fire is ongoing and is being conducted by Louisiana authorities (the CSB typically does not investigate incidents that do not include deaths, wide scale damage, or national news focus). The results of that investigation will not be available for weeks and will probably escape news coverage unless some unusual (read ‘chargeable’) aspects are uncovered.

Based upon news storied I suspect that there was a leak in one of the storage containers on the concrete pad that contained a flammable liquid. Some sort of ignition source (static discharge?) ignited the small pool of spilled chemicals. The initial explosion reported was probably a vapor cloud near the initial fire and probably from the same spill. That small explosion would have damaged nearby containers, contributing to the spread of the fire.

The subsequent reported explosions were probably attributable to nearby containers containing flammable/combustible chemicals being heated to the extent that the gasses expanded in the container until the container was no longer able to contain the pressure. As flammable gasses exited the damaged containers, they were ignited by either the nearby fire or static discharges associated with their release.

At first glance the ‘containment’ at this facility would appear to be rather proforma. The saving grace is that the very large area encompassed by the relatively small curb results in a substantial volume of containment. I have not done the calculations, but it would seem that a large percentage of the containers on site could leak their full contents and the liquid would still be physically contained. Even if one of the storage tanks were to completely drain, it would appear unlikely that any of the contents would flow off site.

This would meet all of the legal standards for containment. The only problem would occur if the leak occurred when there was a large amount of water on site, either due to rainstorms (for which Louisiana is famous) or the application of large amounts of firefighting water. From the news reports that I have seen, it would seem that the local firefighting response did not use large volumes of water; it is usually contraindicated in flammable chemical fires in any case.

The combination of water-soluble (methanol) and water-insoluble (benzene-based chemicals) flammable chemicals on site would cause potential problems with the use of foam for firefighting as they require different types of foam to be used. Still, most fire departments are not going to have access to either type of foam. The best bet in that case is to isolate the facility and stop the fire from moving off-site.

This fire would have been more serious if one of the storage tanks had been a source of the leak that initiated the fire. A fire at the base of one of the tanks could have resulted in a weakening of the tank wall, a resulting collapse and release of the entire contents. The resulting fire and potential vapor cloud explosion would have damaged adjacent tanks spreading the fire throughout the concrete pad area. The overpressure resulting from the larger vapor cloud explosion would also probably have resulted in off-site damage (broken windows and flying debris).

One final note; as is usual with any incident at an industrial facility, at least one news report went back and looked at the regulatory history of the facility involved. They reported on the problems this facility had with the EPA’s hazardous waste regulations. While this is certainly part of the public record, these paperwork violations have little to do with chemical safety and certainly nothing to do with the current incident.

Waste Treatment Facility Fire

There have been a number of interesting news stories (here, here and here for instance) about an explosion and resulting fires at a Southern California waste treatment facility, Southern California Waste Water. It seems that a vacuum truck delivering what was supposed to be non-hazardous waste exploded at the site, spewing an as of yet unidentified chemical mixture on site that ignited various organic materials (including tires of a fire engine and boots of fire fighters; how ironic) on site.

The Business

Looking at the company’s web site it looks like they take in wastes from a variety of customers across the Southern California, de-water the material and prepare a solid material that can be used as a daily cover in selected solid waste disposal facilities. This is a somewhat unattractive, unexciting (on most occasions) and very necessary side of the chemical industry. The company relies on its customers to properly characterize the waste streams that are picked up by various trucking companies specializing in non-hazardous waste hauling.

The vacuum truck goes out to a customer facility and sucks up the waste material from treatment ponds, storage tanks and the like and then delivers it to the SCWW facility. From photographs from the various news articles it appears that the solids in the waste are separated from the bulk of the water (which then is probably sent to a water treatment works). The solids are then combined with other material to form a material that can be used to cover other debris and trash at a landfill.

The Accident

What apparently happened on Tuesday morning was that a large vacuum truck pulled into the facility that contained some material that was reacting chemically within the truck. We don’t know yet what the material was but it seems obvious from the pictures that some sort of gas and maybe heat was being generated by the reaction and the pressure built-up in the tank. While sitting at the facility apparently waiting to unload the pressure built up to the point where the back of the truck flew off and sprayed the contents all over the facility.

As the material dried in contact with air it formed a material that would ignite organic material that it came in contact with; organic materials like plastic, rubber or wood. From the news stories and photos it would seem that a fire truck pulled up on the scene, rolled into the liquid spill and at some point the tires caught on fire as did the boots of some of the fire fighters.

Not know fully what chemicals were involved, and having a river nearby where any fire-fighting run-off would go, the fire departments involved decided not to fight the various fires that sprung up on site and concentrate of confining the incident to the facility.

Injuries

There was a relatively minor injury to a truck driver from the initial explosion (I don’t really like that term in this context as it does not appear there was any fire involved initially, just a pressure build up and catastrophic failure of containment), but there are no real reports of serious chemical injuries on the scene.

Unfortunately, there were some complications at a local emergency room. Some people from the site showed up at the ER complaining about chemical exposure issues. Since they were apparently self-transported they were not decontaminated before arriving at the ER. As a result news reports indicate that there were 12 ER employees that were treated for ‘respiratory distress’. Since we don’t yet know what chemicals were involved these may have been caused by chemical exposure reactions or just a very typical and understandable psychological reaction of people to an unknown and unpleasant odor associated with a potential chemical hazard.

This points out a problem that all ER’s must prepare for when there is an incident at a nearby chemical facility. While we expect the local hazmat team and ambulance teams to ensure that transported individuals are decontaminated before leaving the scene, people that self-transport are usually not so careful. It would be a good idea to set up a triage area outside with decontamination equipment and appropriate PPE for the decon team to avoid contaminating the ER when a chemical incident takes place in the local area.

Investigation On-Going

The investigation into this incident is on-going with local agencies, the EPA and OSHA probably being involved. Since there were no deaths or serious injuries reported to date, it is unlikely that the Chemical Safety Board will be involved.

A major focus of the investigation will certainly be the facility from which the truck load of waste originated. Also sure to be looked at will be the clean out procedure used on that truck before the last load was picked up to see if cross contamination of waste streams may have been the culprit.